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By SAHENDRA SINGH, SANJIT KUMAR PAL, DHARMITA HORO

This study was carried out in Ichadih to map the sulfide/gold mineralization using combined electrical resistivity tomography (ERT) and self-potential (SP) methods. No geophysical analysis has been carried out to delineate such ore deposits in the area. Thus, the study provides a different approach for approximate location and extension of the quartz reef associated with sulfide/gold mineralization. It also provides the elementary idea for further detailed subsurface investigation in terms of geological and geophysical approach. 

By S. K. Kawatra, T. C. Eisele

Production of highly-cleaned coal for advanced utilization schemes requires close control of the coal ash content at very low levels. For this purpose, a sensitive, low-cost, robust on-stream ash analyzer is needed. The development of such an instrument based on x-ray backscatter and fluorescence is described, including features to improve its sensitivity at low ash levels. The performance of the resulting device in testing a real coal sample is discussed.

Jan 1, 1990

By M. J. Hrebar

In the summer of 1990, a study was conducted to document large tractor (i.e., Caterpillar Dl1N) utilization in surface coal mining. The tractors were found to be utilized as primary production machines and in combination systems with blast casting and draglines and blast casting and excavator/truck systems. In addition, dozers were used to prebench ahead of a primary dragline system. The study also established ranges and averages for Dl1N operating costs and mechanical availability. Based on simulated production of various tractor dozing applications, the potential for low cost coal stripping was suggested (Hrebar, 1991). A follow-up study, also funded by Caterpillar Inc., was conducted in the summer of 1991 to determine actual production rates in two dozer stripping applications. These actual production rates would then serve as a foundation for estimates of stripping costs. This paper presents the results of the studies in a contour and a cast application.

Jan 1, 1992

By D. Krzyszton, P. Czaja

Mining explosions in rocks originate stress waves of great intensity, which crush the surrounding rocks and are then propagated as a seismic wave. Seismic waves are the cause of dynamic loading of pillars and their subsequent destruction. In calculating safe dimensions for inter-room pillars, not only the stresses conditioned by overburden pressures should be taken into consideration, but also the dynamic stresses caused by explosion. This is of particular importance for pillars with great specific acoustic impedance which have been destroyed mainly by the reflected seismic wave. It is possible to take dynamic loading into consideration in the calculation of pillars when the parameters of the propagation wave, the dynamic elastic constants of rocks, the strength properties of rocks, the strength properties of rocks subjected to dynamic loads and the parameters of the blasting charge are known. An example of the calculation for the safe width of an inter-room pillar subjected to the seismic effect of an explosion is given and the possibilities of reducing the dynamic loading of pillars are discussed.

Jan 1, 1982

By A. T. Yu

As a nation, we have been known as perhaps the most wasteful in history. From the perspective of engineers and builders on the other hand, planned obsolescence and demolition did beneficially pave way for growth and provided environment for new businesses. Recent economic recession and intense competition from overseas, however, have drastically changed the economics. The high cost of capital and the demise of indiscriminate plant expansion have totally altered the way we conduct our business and run our operations. As a response to increasing demands for better efficiency with little or no funding available, everyone is forced to make do and do better with whatever little he has. Today it nay not be an exaggeration to state that modification of existing facilities may have finally emerged as a way of life. This paper will outline examples of how several companies have effectively modified existing facilities to do more and do it efficiently without having to demolish everything and/or to spend a fortune.

Jan 1, 1985

By Vladimir L. Konyukh

Robotics is topical for mining owing to deterioration of miner's safety as a depth of winning, limited functions of traditional mechanization and automation, rise of miner's labor cost. Mining robot is an autonomous mining machine with a free programmable control that provides a multifunctional use of working head. After analysis of world publications the database “Technological applications of robotics in mining" has been built. In most cases robots are suggested for imitation of miner's motions. The following shapes of robotics had been classified for mining: technological robot as a flexible controlled mining machine, remote manipulator, mine rescue robot. The problems of both non-repeated environment recognition and telepresence without direct visibility must be solved. The more a robots integration is the less investments and the more efficiency are. Computer simulation of robotics-based mining is founded on a base of 6 robots functional models, Petri nets and library of 30 robotized technologies. There are some examples of mine robotization in the paper.

Jan 1, 1996

By Charles E. Glass

As partial implementation of the Surface Mining Control and Reclamation Act of 1977, the Office of Surface Mining (OSM), Department of Interior, has requested each state to inventory hazardous abandoned mining areas within their boundaries. Primary interest is in such areas .as unstable waste-banks, subsidence and slumping, contamination of water supplies, and preservation of overall aesthetic qualities through reclamation. In addition to the concern expressed for abandoned mining areas, the legislation requires a complete inspection of operating mines quarterly and a partial inspection monthly. In Arizona copper has been mined for over 100 years and coal and uranium mining promises to expand in future years. The OSM requirement for a waste inventory and frequent monitoring of Arizona's large, widely spaced mines places a severe demand on limited personnel and operating budgets. Remote sensing by satellite provides an attractive and effective approach to aid the inventory and monitoring requirements of the OSM legislation.

Jan 1, 1979

By D. Kruse

Top-down constructed large-diameter (up to 90 m or 300 ft) shaft design and constructability issues present an interesting suite of challenges and opportunities highlighted in this paper. The study covers 2D and 3D finite element models used to analyze various failure modes, evaluate the shaft liner and internal structures' response to seismic loading, assist in segment design and assess final structural design tradeoffs. Efforts to achieve economic advantage over conventional heavy civil practices have prompted innovative solutions for ring and segment design, ring build assembly and annulus backfill grouting. Intended for soft ground conditions, relationships between soil parameters and structure design are also explored. Mining Engineering, 2011, Vol. 63, No. 9, pp. 81-88. Official publication of the Society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By Lee Herold Storey

Groundwater remediation is growing in occurrence in the western United States. Groundwater remediation programs are regulated by state water quality statutes. The remedial action plans implemented under these statutes may conflict with well-established existing rights to withdraw groundwater for beneficial use. This paper discusses how the states of Arizona, Colorado and New Mexico administer conflicts between the need to withdraw and remediate groundwater with the existing rights of others to withdraw groundwater for beneficial purposes.

Jan 1, 1991

By J. W. Merks

Spreadsheet software is used to convert test results for drill core samples into borehole statistics such as volumes and masses of in-situ ore, metal contents and variances of metal contents. The properties of variances and the sampling variogram play a pivotal role, The additive of property of variances gives a sound scientific basis to the calculation of confidence limits for metal contents and grades as a measure of the risks associated with estimating reserves and resources.

Jan 1, 2000

By Peter G. Mason

Pressure oxidation is now a well estab­lished process for the treatment of refracto­ry gold ores and concentrates. The process utilizes pure oxygen to oxidize mineral sulphides in an aqueous slurry at elevated temperature and pressure. Gold released from the sulphides becomes amenable to subsequent cyanidation. A major component of the operating cost of this process the supply of oxygen. The quantity required is dependent on the sul­phide grade, the extent of oxidation and the percentage utilization of the oxygen. As the sulphide grade is fixed and complete oxida­tion is generally required to maximize gold liberation, the only opportunity for saving in oxygen consumption is to improve its utilization. Under circumstances where the feed material contains substantial carbonate, oxygen utilization can be improved by strip­ping carbon dioxide from the autoclave vent and recycling the associated oxygen. Fluor Daniel Wright included an oxygen recycle circuit in the Getchell pressure oxidation plant, which is operated by First­Miss Gold in Nevada. FirstMiss Gold has applied for patent rights to the process as implemented at Getchell.

Jan 1, 1990

By Ivano Andreis, Giovanni Valent

The Yindaruqin Irrigation Project is designed to irrigate 57,000 ha of land in the central part of Gansu Province of People's Republic of China. Water for the Project will be diverted through an 87 Km long feeder canal which will convey 36 cubic meters per second from an intake on the Datong River. (Fig. 1) The feeder canal consists of approximately 10 Km of open channels, 75 Km of tunnels and 2 Km of siphons and aqueducts. This is the biggest self-flowing irrigation water control project in the Northwest of China and it is among the most interesting projects in China for the geological and environmental conditions. Nearly half of the investment in the Project is a World Bank Loan and contractors were chosen by means of international bidding. The Italian Company, CMC Ravenna, succeeded in answering the bidding for the construction of tunnels 30A and 38, perhaps the most difficult in the Project, submitting a TBM alternative to the conforming drill and blast contract recommendation.

Jan 1, 1993

By Abdullah Arik

The resource classification methodologies have always been a topic of research and debate. There are both traditional and Geostatistical methods used in practice. Because of the uniqueness of each ore deposit, it seems almost impossible to have a single industry-accepted norm for resource classification. Therefore, some practitioners have adapted the methodologies to suit the deposits they are working on, but many simply use the methods they are comfortable with. Another reason for the existence of varying classification methodologies is the lack of an easy and established way to measure the confidence in the estimates. Therefore, their classification becomes a subject of debate. In this paper, a new approach is offered to classify the resources using a "Resource Classification Index." The approach using this index takes into account the local variation, the spatial data configuration around the block being estimated, as well as the traditional distance measures. A case study for a gold deposit is presented to demonstrate how this new index can be used to classify the resources. The results from this approach are compared to those from two popular classification methodologies.

Jan 1, 2002

By A. Arik

An accurate estimation of mining block grades continues to be a challenging task for ore reserve practitioners. Two of the factors that affect the accuracy of the estimates are the estimation method used and the variability of the mineralization in the deposit. The objectives of the study are twofold: Firstly, to see how different estimation methods perform on a given deposit. Secondly, to determine the impact of particular nature of the mineralization on the results. The comparison of several estimation methods for the prediction accuracy is performed using the conditional simulation results as the basis.

Jan 1, 2000

By Peter J. Lawson, John A. Rideout, Gregory W. Dicinoski

A considerable body of literature directed towards optimising the efficiency of gold and silver extraction from cyanide leach liquors has appeared in recent years. A few examples from dissolution to solvent extraction to adsorption in carbon-in-pulp (CIP) and resin-in-pulp (RIP) operations follow. Selective leaching of gold from copper-gold ores using ammonia-cyanide mixtures extends the % copper which may be tolerated in ores (Ruane, 1991, LaBrooy et al., 1991, Costello, 1991). The removal of copper and recycling of cyanide from high copper ores is another important development (Sceresini and Staunton, 1991). Solvent extraction of alkaline cyanide liquors (Riveros, 1990, Mooiman & Miller, 1991) and solvent aided elution in CIP (Muir, et al., 1985) look promising. Recent definitive papers on the mechanism of adsorption of aurocyanide by activated carbon should lead to more efficient use of CIP (Adams and Fleming, 1989, Klauber, 1991). Strong and mixed weak-strong base resins have been applied in RIP for aurocyanide extraction in Russian Plants since the 1970's (see for example Borovskii et al., 1985, and references cited in Fleming, 1988a). Fundamental studies on applications of commercial weak and strong base resins-in-pulp (Fleming & Cromberge, 1984a, b, Fleming 1988a, Hosking 1984, Riveros and Cooper 1987) have generated much interest in RIP. Detailed comparisons of CIP vs RIP efficiencies at Mintek in South Africa (Fleming et al., 1988b), and the inefficiency of CIP in contact with clay led to the commissioning of the strong base RIP Golden Jubilee plant in 1988. Its operation and improvements have been reported (Seymore and Fleming, 1989, Fleming & Seymore, 1990). The use of anion exchange membranes for aurocyanide extraction shows some promise (Mauthoor et al., 1991). However, the development of new gold specific resins at Mintek (Green et al., 1984, 1986, 1990, Johns and Green, 1991) and elsewhere (Asker et al., 1987, Wilson et al., 1987, Harris et al., 1992) should improve the viability of RIP processes. The polydiallylamine gold specific resins (Hodgkin & Eibl, 1988, Fawell et al., 1992a, b) have high capacities for auro cyanide recovery from high concentration liquors. The use of guanidine based liquid and solid ion exchange extractants for gold was recently reported by the Henkel Corporation (Kordosky., et. al., 1993). Such specific resins tailor made for gold and/or silver cyanide extraction should lower overall cost by improving metallurgical efficiency. In the case of strong base resins this selectivity largely eliminates the problems of poor base metal elution and/or poisoning. The work reported here outlines the approach taken at the University of Central Queensland to synthesize sterically hindered strong base anion exchange resins which are designed to have high selectivity for auro- and argentocyanide complexes. It summarises selectivity tests on low grade cyanide leach liquors from several mines. It also examines an RIP vs CIP comparison, and investigates the elution properties and cycling of one such promising resin.

Jan 1, 1993

By D. R. Spears

The Bureau of Mines has investigated the fundamental aspects of shear-flocculation using a rapid, in-situ particle size analyzer. Silica was stirred in the presence of an aliphatic amine to determine the effects of collector coverage, stirring speed, and solids concentration on the kinetics of shear-flocculation. The results showed that shear-flocculation is a two-stage process. In the first stage, mean particle size increased rapidly in the first 1-2 min of reaction; in the second stage, an equilibrium was set up between the rate of floc growth and floc decay. Collector dosage affected the position of the equilibrium by altering the number of surface sites for particle-particle attachment. A minimum stirring speed was necessary for shear-flocculation to occur and was dependent on solids concentration and collector dosage. This speed was the minimum necessary for particles to overcome the electrostatic energy barrier which kept conditioned particles dispersed. Larger particles flocculated more rapidly. At very high stirring speeds, large flocs became unstable, resulting in a narrowed particle size distribution in the slurry.

Jan 1, 1993

By P. C. Kapur

For mineral processing spirals, mathematical force equilibrium models are sought to extend the spiral performance envelop. In Part 1 of this report, a complete geometric description of the helical spiral and its trough or channel contour is provided. The secondary circulatory fluid motion in the transverse direction that develops when water flows down a tightly turning curvilinear path and its implications for gravity separation are discussed. Different forces that act on the particle during its passage through the spiral are enumerated and quantified for a better appreciation of their relative contributions and roles in the separation process. Three force equilibrium models from the hydrology literature on sed iment transport are employed to simulate a typical spiral. While the results are promising in that the models mimic the broad performance characteristics of the spiral, what is needed is a more general spiral model taking explicit cognizance of the missing components essential to the spiral description. These are such components as centrifugal force and the steep tangential slope of the channel deck. Results of this latter exercise are deferred to Part 2.

Jan 1, 1996

By Ronald J. Roman

As in every business venture, the primary objective of a mining operation is to make money for those who supply the venture capital. Therefore, all decisions concerning the operation of the mining operation should be made in light of the resulting effect on profit. The ultimate control is on profit, but the process is controlled, for example, by aiming for a recovery or concentrate grade knowing its effect on profit. The normal procedure used to determi.ne the profitability of a venture is to "present worth" all costs and incomes back to some arbitrary year zero. Every company has formed a management decision as to what it will require as a minimum return before it will undertake an investment. Once the economic analysis is completed, investment will be made only if the venture shows a positive present worth. If two alternatives are available, the alternative with the larger positive present worth is the one chosen. The same principles can be applied to the selection of a production schedule.

Jan 1, 1971

By Z. Eisenstein, H. Heinz

INTRODUCTION Contemporary underground transit systems often require cross sections which are not adaptable to shield tunnelling. Due to the frequently large dimensions of these cross sections, which are normally situated at shallow depths and in soft ground, full face advance is not feasible because of ground control and construction requirements. Ground deformation and face stability are controlled by "staged excavation", which consists of sequentially driving smaller, specially arranged, individual headings hence avoiding full-face excavation. Shotcrete is normally used for initial support and these tunnels are frequently described as applications of the New Austrian Tunnelling Method (NATM). Figure 1 illustrates the relative size of large cross section tunnels with respect to conventional shield tunnels. Within the scope of this paper, 'large' cross sections are defined as those whose continuous (i.e., without intermediate pillar support) cross sectional excavated area exceeds 60m2. This definition includes most double track highway, railway and subway tunnels, subway stations and some single track railway tunnels. Excavation schemes which have been more frequently used for continuous cross sections (i.e., with no intermediate pillars) are presented in Figure 2. This classification is an extension of that presented previously by Eisenstein et al. (1986). The symbols used for classifying the excavation schemes are formed by the letter T (for "type"), followed by a number, which represents the number of excavation stages fully embraced by a shotcrete ring, termed "cells" by Lessmann (1986). The numbers inside the cross sections in

Jan 1, 1989

By C. E. Zebula, F. F. Aplan, R. S. Datta

The hydrophobicity of oil shale was found to follow the sequence R-5 > Mahogany >> Eastern. Further, hydrophobicity was found to correlate with the total organic carbon (TOG) content, decreasing with increasing specific gravity of raw oil shale pieces. Differences in hydrophobicity from piece to piece indicate that gravity preconcentration would be much more effective for Western than for Eastern oil shales. Purified kerogen concentrates and low specific gravity fractions (<2.0) of raw Western oil shale samples show critical surface tension of wetting values of [y]c = ~35 mNm -1, and for a kerogen concentrate from an Eastern oil shale [y]c = ~46 mNm-l. This infers that dust from oil shale mining operations can be suppressed by surfactant solutions similar to those used to suppress coal dust.

Jan 1, 1988